I have wrangled with this question a lot over the years. With technology changes, so has my answer.
Life before the Internet (LBI – my personal acronym), graphic designers would often keep the native files (originals) as their own. The clients were allowed to use what was created for them but if the client wanted the native files, he/she would need to pay more. Photographers also followed this same protocol.
There were good reasons for this. Having been a professional photographer myself, LBI, if you kept the original negatives, the client could only order photographs through you. This was simply a good business model.
Also having been a graphic designer LBI, I practiced this to some extent. And when I started doing web design (1999), I continued that practice. But I could see, as time went on, this was not necessarily the best way to handle it.
Some Web developers and graphic designers still do but I don’t.
The reason I don’t do this now is it becomes too much of a minefield with clients and possibly my reputation. For me this is less of a question of what is fair or right and more about really serving my clients in the best way I can while still being able to make a living at this work that I love so much.
The minefield happens when clients are unaware of this until they want the files, don’t remember agreeing to it (even though it might be in a contract) or understand what this means.
My agreements state:
I own the files but I give my clients a license to use them.
I retain the right to use the work I have done for them in my own advertising, website, etc.
I will give them the files after the project is finished, if they want them.
I find no glee in keeping clients from hiring someone else if they, for whatever reason, have decided to do so, to use these files for other reasons in their businesses.
When this has happened, frequently clients have returned to me for additional work. It doesn’t have to mean they don’t want to work with me anymore. It often has meant they want to have some work done in-house, making it more affordable for them. They would then hire me for the more difficult projects which they can then afford.
What is the takeaway?
Find out from your professional at the beginning of the work what his/her practices are for retaining native files. If you don’t like that answer and you really want to work with him/her, ask if you could do it another way.
If you do agree with the professional to withhold the native files, then live by that agreement and pay for buying them outright if you want to have them.
Do not hold it against your professional for using standard business practices.